Time switch for motors



June 22, 1954 -J. M. LAIHO TIME SWITCH FOR MOTORS 2 Sheats$heet 1 FiledJune 3, 1949 June 22, 1954 TIME SWITCH FOR MOTORS Filed June 3, 1949 2Sheets-Sheet 2 INVENTOR.

BY JaZmerMlai/zo J. M. LAIHO I 2,682,028

or the cancelling crank Patented June 22, 1954 TIME SWITCH FOR MOTORSJalmer M. Laiho, Skokie, Ill.,

assignor to Felt &

Tarrant Manufacturing Company, Chicago, 11]., a corporation of IllinoisApplication June 3, 1949, Serial No. 97,039

'7 Claims. 1

This invention relates in general to electric circuit controllingmechanism, and more particularly to a novel time switch forautomatically opening a motor circuit at the end of a predeterminedinterval.

A principal object of the invention is the provision, in a motor drivenmachine having manual control members selectively operable to initiateoperation of the machine and cause the closing of a switch which resultsin energization of the motor, of means automatically effective to openthe switch to de-energize the motor at the end of a predetermined timeinterval after operation of the last-to-be-operated of such manualcontrol members.

Another object of the invention is to cause the motor of a calculatingor business machine to be turned oil automatically when the operator hasfinished using it, so that carelessness on the part of the operatorcannot result in the machine motor continuing to run indefinitely.

More specifically, the present invention comprises the addition to amotor driven calculating machine, having the usual digit keys andcancelling crank as manual control members, of time switch mechanismoperable to start the motor in response to actuation of any digit keyand to stop the motor of a predetermined time such starting of theautomatically at the end interval beginning with motor.

Another object is the provision of such time switch mechanism which willbe reset automatically by each subsequent operation of a control memberwhich is effected before the expiration of such time interval, startingfrom the time of manual release of the last control member to have beenoperated, so as to avoid unnecessary starting and stopping of the motorduring the performance of any normal series of related calculations.

Numerous other objects and advantages of the invention will be apparentas it is better under stood from the following description, which, whentaken in connection with the accompanying drawings, discloses apreferred embodiment thereof.

In the drawings:

Figure 1 is a fragmentary elevational view of a calculating machineembodying the instant invention, as seen from the right side of themachine, showing the usual cancelling crank and the normal positionassumed by the time switch mechanism following dr-energization of themotor;

Fig. 2 is a detail rear elevation of the time switch mechanism, as seenfrom the right end of Fig. 1;

Fig. 3 is a fragmentary elevation similar to Fig. 1, showing thepositions assumed by the various parts of the time switch mechanism uponactuation of a manual control member;

Fig. 4 is a detail view similar to Fig. 3 of the switch-opening rack andimmediately associated parts, showing the positions assumed thereby justprior to automatic opening of the switch;

Fig. '5 is a longitudinal elevation of the machine, with parts omitted,as seen from the left side thereof, showing the power drive connectionsfrom the motor to the time switch mechanism and the means for actuatingthe latter in response to digit key operation; and

Fig. 6 is a diagrammatic view of the motor circuit.

Referring more particularly to Fig. 5 of the drawings, reference numeral2i designates in general a calculating machine of the type disclosed inUnited States Letters Patent No. 2,063,962, issued December 15, 1936,and my prior U. S. Patent No. 2,410,823, issued November 12, 1946, thisfigure corresponding generally with Fig. 2 of each of said priorpatents.This calculating machine is provided with a plurality of denominationalorders of accumulator and actuating mechanisms, the latter being mountedon skeleton frame members or partition plates 22 held together in spacedrelationship by transverse tie rods 23, and registration control meansincluding a column of digital control keys 24 for each such order whichare selectively manually depressible to determine the digital degree ofactuation to be imparted by their associated actuating mechanism to theaccumulator. Such mechanism is fully described in said prior patents, sothat a more particular description herein is not necessary, referencebeing had to those patents for a complete explanation of the specificarrangement of the parts and operation of this type of calculatingmachine, including an electric motor 44 drivingly connected by suitablegearing (Fig. 5) with a power drive shaft 45 extending transversely ofthe machine across the several denominational orders and comprising anelement of the cyclically operable registering means of the machine.

It is sufficient for a complete understanding of the present inventionto know that in this type of calculating machine, which comprises onlyone of many possible devices with which the instant invention may beemployed, depression 3 of any digit key 24 causes its stem All to engageand move downwardly a longitudinally extending bar 28 (Fig. 5) formingpart of a parallel motion device, one such device being located in eachdenominational order of the machine. Each bar 58 is pivoted at the frontat 49 and at the rear at 51 to levers 52 and 53, respectively, which inturn are pivoted upon cross shafts or rods 54 extending through thepartition plates 22. Completing each parallel motion device is a link E5which is pivotally connected at 58 to the front lever 52 and at 51 tothe rear lever 53. It will thus be seen that depression of any digit key24 will cause forward movement (to the right in Fig. 5) of the lowerlink '55 of the associated parallel motion device, and it is thisresulting forward movement of the stud 56, comprising the pivotalconnection between the link 55 and the lever 52, that is employed inconnection with the present invention, in a manner to be fully describedhereinafter. For convenience, all of the reference numerals so far usedherein are the same as those applied to the same parts in my said priorPatent No. 2,410,823.

As is customary in this type of calculating machine, other registrationcontrol means also are provided comprising means for zeroizing orcancelling any registration from the accumulator. In the prior patentspreviously referred to, such zeroizing of the accumulator isaccomplished by rocking the supporting frame of the accumulator todisengage the latter from its actuating gears, and the specificmechanism for accomplishing this cancelling function is fully disclosedin U. S. Letters Patent No. 1,357,748, issued November 2, 1926. Thezeroizing mechanism of the instant machine is substantially identical tothat described in this latter patent, so that only so much thereof isillustrated in Fig. 1 herein as is necessary to a complete understandingof its structural and functional relationship with the presentinvention. A short transverse shaft '10 (Fig. l) is journaled in asuitable bearing in the right hand side plate 22, and the lower end of azeroizing control handle or cancelling crank '11 is secured to the outerend of this shaft. A segment 12 is fixed upon the inner end of thisshort shaft 10, and a link 13 pivotally interconnects the segment 72 anda depending lever "14 that is pivoted at '15 on the machine frame. Theseparts are numbered the same as their counterparts in Patent No.1,357,748, and as explained in detail in said patent, forward movementof the upper end of cancelling crank 11 (counterclockwise movementthereof viewing Fig. 1) will move the link '13 forwardly to swing thedepending lever '14 in a counter-clockwise direction to actuate asuitable rock shaft which effects the gear detraining and accumulatorzeroizing previously mentioned.

Pivotally secured at its forward end to this depending lever 14 and thelink 13 is a rearwardly extending link 121, the rear end of which ispivotally connected to the upper end of a lever 153. This lever 153 isfixed intermediate its ends on the right hand end of a cross shaft 152having suitable bearings in the skeleton frame members 22 and extendingtransversely through all denominational orders of the machine. The lever153 is urged in a clockwise direction (viewing Fig. 1) by a spring 155secured thereto at one end, adjacent the lower end thereof, and at itsother or forward end to a cross shaft 156 mounted in and extendingthrough the frame plates 22. These several parts are numbered herein thesame as their counterparts which are fully disclosed in U. S. LettersPatent No. 2,021,393, issued November 19, 1935. Counterclockwisemovement of the cancelling crank '11 from its normal position of Fig. 1to effect zeroizing of the accumulator, in the manner noted above, thuswill carry the link 12'1' forwardly to impart counter-clockwise movementto lever 153 from its position of Fig. 1 to its position of Fig. 3, andalso considerably beyond the position of Fig. 3. The resulting rotationof shaft 152, as speifically explained in said prior Patent No.2,021,393, releases error control or key locking mechanisms which mayhave been set by mismanipulation of one or more digit keys 2 1. It isthe rearward movement of the lower end of this lever 153 thus resultingfrom operation of the cancelling crank '11 that is employed inconnection with the present invention.

To adapt this otherwise old lever 1'53 for use with the novel mechanismcomprising the instant invention, its lower end has been lengthened andprovided with an outwardly extending tooth 261. This tooth 201cooperates with a notch 282 (Fig. 1) in the forward end of the lower armof a two armed pawl 203 pivotally mounted at 204 on a link 205. Agrasshopper type of spring 2136 mounted on the pivot 2M engages theunderside of the link 205 at one end and the forward edge of an upperarm 221 of the pawl 233 at its other end. The lower arm of the pawl 263has a lat eral extension or shelf 20B normally engaging the lower edgeof the link 295 to limit clockwise movement of the pawl 2113 by thespring 206. A stud 2119 is mounted on the adjacent skeleton frame member22 for cooperation with the upper arm 20! of the pawl 2113 in a mannerto be later described.

The forward end of the link 2115 is provided with a slot 211 slidablyengaging the shaft 156. A spring 212 is connected at its forward end tothe cross shaft 156 and at its rear end at 213 to the link 205 tonormally maintain the latter in its position of Fig. 1 with the rear endof the slot 211 in abutting engagement with the shaft 155. Adjacent itsrear end, the link 2115 is pivotally connected at 21 1 with the upperend of a lever 215 in turn pivotally mounted at its lower end on a crossshaft 216 mounted in the frame plates 22. The rear end of the link 2% ispivotally connected in any suitable manner at 211 with the forward endof a link 213 in turn pivotally connected at its rear end with anupwardly extending arm of a bell crank lever 219. This lever 219 ispivotally mounted on a cross shaft 221 on which shaft the forward end ofa latch pawl or holding detent 222 is also pivotally mounted. Thisholding pawl 222 is provided with a laterally extending stud 223 whichis held in engagement with the under surface of the lower, rearwardlyextending arm of the lever 21!] by a grasshopper type spring 224, thelatter being mounted on the cross shaft 221 and engaging the undersurface of the stud 223 at one end and the forward edge of the upper armof the bell crank 21!! at its other end.

A stud 225 extends laterally of the machine, but not inwardly sufficientto contact the lever 219, for movement-limiting engagement with theforward end of a switch-opening ratchet memher or slide bar 226. As bestseen in Fig. 2, an auxiliary frame is provided for supporting thoseparts of the instant time switch mechanism mounted at the rear of themachine, which comprises a pair of vertical side plates 221 securedtogether in parallel spaced relationship by suitable bolts and spacersleeves, as indicated at 228, this sub-frame assembly being mounted inany desired manner on the inner side of the right hand frame plate 22,and the outer plate 221 carries the laterally extending stud 225. Theouter plate 227 of this time switch sub-frame alsois provided with apair of inwardly extending shouldered studs 229 which are slidablyengaged, respectively, by a pair of horizontally disposed slots 23!formed in the ratchet slide bar 225. This ratchet slide bar 226 thus ismounted for horizontal sliding movement, and it is provided on its loweredge with a plurality of ratchet teeth 232 adjacent its forward end forcooperation with the holding pawl 222. The pawl 222 normally engages theforward one of these ratchet teeth 232 to maintain the ratchet slide bar226 in its rearmost position of Fig. 1, wherein an insulated roller 233mounted on the rear end of the slide bar 226 and extending laterallytherefrom engages against the lower end of a spring contact member 234to maintain the contact thereof out of engagement with the contact of asecond depending contact member 235. These contact members 234, 235comprise a switch connected in series with the motor 44. As shown inFig. 6, the contact member 234 is connected to one side 23% of asuitable source of electrical energy, the other side 23? of such supplybeing connected to one side of the motor 44, and the other side of thelatter being connected by a lead 238 to the other contact member 235. Itwill be under stood that any desired circuit arrangement other than thatillustrated in Fig, 6 may be employed, so long as the closing andopening of the switch comprising the contact members 234, 235 results inthe energization and de-energization, respectively, of the motor 44.

Referring again to Figs. 1 and 2, the upper ends of the contact members234, 235 are rigidly mounted in a block 239 of insulating material whichis secured intermediate its ends by rivets 2, or the like, to a bracket242 comprising an upwardly and rearwardly extending end portion of theouter side plate 221, the inner plate 221 terminating at its upper rearend adjacent the forward edge of the insulating block 239. Such mountingof the contact members 234, 235 on this insulating block 239 preferablyis accomplished by providing the contact members with lateral extensionsat their upper ends (Fig. 1) in the form of ears 243 extending therefromrearwardly and forwardly, respectively. Each of these cars 243 isconnected to the insulating block 239 by a pair of rivets 244, the upperone of which preferably is hollow and formed at its inner end as asocket to receive the ends of the leads 236 and 238, respectively (Figs.2 and 6).

A transverse shaft 245 extends between the sub-frame plates 22'!adjacent their upper edges, being suitably secured thereto in anydesired manner, upon which the upper end of a dependin lever 246 ispivotally mounted. As best seen in Fig. 2, this upper end of the lever246 is reversely'bent to provide a saddle-like hub portion havinglaterally spaced lugs through which the shaft 245 extends to insurelateral stability of the lever. A spring 24'! is connected at its rearend to this lever 24B below the shaft 245 and at its forward end to ashaft 248 extending transversely through the machine. The lower end ofthe depending lever 246 is maintained by this spring 241 in engagementwith a stud pin 249 extending laterally from the ratchet slide bar thanits associated second roller 25in.

so mounted on-this gear 26i 6 226. Also mounted pivotally on the shaft245 is a bell crank lever 25! which, as seen in Fig. 2, is provided witha laterally extending, reversely bent hub portion engaging the shaft inthe same manner as the hub portion of the lever 246. These hub portionsof the levers 246 and 25| are so dimensioned as to be pivotably confinedadjacent each other between the inner surfaces of the side plates 221 toprevent lateral movement of the levers. The upper arm of the bell cranklever 25! extends forwardly and is connected at its forward end to theupper end of a spring 252, the lower end of which in turn is connectedto a suitable stud extending inwardly from the outer sub-frame plate227. The lower end of the depending arm of this bell crank lever 25lterminates adjacent a shouldered stud 253 extending between, andsuitably mounted in, the sub-frame plates 22! (Fig. 2'). Above this stud253, the lower end portion of the lever 25! has a stud shaft 254 mountedtherein which extends outwardly from the lever and pivotally supports apawl 255 at its outer end which is disposed in vertical alignment withthe ratchet slide bar 225 which it is adapted to move rearwardly of themachine. Mounted on this stud shaft 254 is a "grasshopper type spring256, one end of which engages the forward edge of the lever 25| and theother end of which engages the lower edge of the pawl 255 to urge thelatter in a counterclockwise direction (Fig. 1) on the shaft 254 toengage the rear end thereof with actuating teeth 25'! provided on theunder edge of the ratchet slide bar 225. This slide-actuating pawl 255is provided with a depending tail piece which cooperates with thetransverse stud 253, in a manner to be later described in detail.

Intermediate its ends, the depending arm of the bell crank lever 25I isprovided with a later-- ally extending lug 25% (Figs. 1 2) having a rearsurface parallel with the adjacent rear edge of the lever 25E andextending therefrom inwardly of the machine, and an upper edge (Jig. 4)sloping downwardly toward the main. portion of the lever 25!. This rearsurface and upper edge of the lug 258 function as cam surfaces andcooperate, respectively, with a first cam roller 259 and a second camroller 255 of each of two pairs of such rollers mounted on the outerside of a gear 25L As best seen in 1, this gear 26l'is rotatably mountedupon a horizontal shaft 262 extending between, and supported thesub-frame plates 22?. The said first cam rollers 259 of each of the twopairs of rollers 255', are disposed diametrically opposite each other,as are the second cam rollers 23% of each such pair of rollers, and eachroller 259 is mounted at a greater radial distance from the shaft 232The gear 264 is actuated by a pinion 2E3 meshing therewit (Fig. l),which is rotatably supported on a s table shaft 263 secured to thesub-frame plates 221. A gear 264 is similarly mounted on this shaft 263'and is rigidly connected to the pinion 253. This gear 264 in turn mesheswith a pinion 265 secured to the power drive shaft 45. Since the motor54) through the gear train illustrated in Fig. 5, drives the power driveshaft in a clockwise direction (viewingFig. l), the gear 251 likewise isrotated in clockwise direction, through the agency of the pinion 255,gear 264 and pinion 263; any desired gear ratio may be employed betweenthe power drive shaft 55 and the gear 26!, and the cam rollers 259, 260are that they will assume 7. substantiallytheirpositions--of Fig;liafter the motor 44 has been de=energized andt-the several parts driventhereby have come--to rest. As shown in Fig; 1,: pawl 255'thenwillbe-disengaged from ratchet slide bar'226.

The means for .releasing1the' ratchet slide bar 226-"in response 'toactuation of the cancelling crank 1| comprises the lever'l53; which isswung from-its normal posit-ionof Fig; l to that of Fig. 3 by virtue ofthemembers 16,12, .13, 14 and=l21 interconnecting: it with thecancelling-prank 1 l the tooth 26! on this lever 153,- the: pawl-.263,links 265mm 2 i6, andcthe leverr2 [6, which, when thus moved to theirpositions of Fi 3,- release theholding pawl 222 from the ratchet slidebar 226; Since "the pawl 255 normally is in its disengaged positionofFig.: 1 at .this'ti-me, spring 261 thus will be permitted to. swinglever 246 clockwise from its position 'of Fig'i. l to slide theratchethar 226-toits position of-Fig: 3, through the agency of stud pin246: Such forward-movement of theratchet slide-bar 226-is limited bycontact with the stud 225. Additional time switch controlmeans areprovided-,..which will now bev described, comprising: mechanism forsimilarly releasing the ratchet slide bar 226 in response to actuationof armor thedigitkeys 24-of the machine:

Referringto Figs 5, an upstanding finger 266 is provided in eachdenominational order of the machine forcooperation at its1upper endwi-th thevassociated stud 56 which comprises the front pivotbetween thelink 55 and' the lever 52 of the keyeactuated parallel motiondevice of=that order. Thelower ends of each of these fingers .266'are crimped, orotherwise suitably rigidly-secured, to a rock shaft 261 extendingtransversely acrossthe machine. i the present embodiment of the inventi'on, this shaft 261 is illustrated as being rectangular in crosssection, and His rotatably mounted at 266 in any suitable manner at eachend in a supportingplate 269.- These end plates 26!! are supported bythe crossshaft I56 and an adjacent transverse tie rod 23. Consequently,

depression of any one of the digit keys 24 -will cause the finger 266 inthat denominational order to be swung forwardly at its upper-end fromits full line to its broken line position of Fig. 5.

Referring now to Figs. 1 and 3, the rock shaft 261 is provided adjacentits right hand end with an upstanding lever 21! secured thereto at itslower end in similar manner-to thefingers 266. The upper end of thislever 211 is pivotally connected to the forward end of a link 212, therear end of which is pivotally connected to the upper arm of a bellcrank lever 213. The bellcrank lever 213 is pivotally mounted on a shaft214 extending transversely through the machine, and is'providedat itslower end with a laterally extending stud pin 216- This pin 215 normallyengages the forward surface of a shoulder "216 formed on the upper edgeof the 'link- 265 adjacent the forward end thereof. When: the fingers266 are in their normal full line positions of Fig. 5, the lever 21!,link 212 and bell -crank 216 are disposed in their full line positionsofFigs. l and 3. Forward rocking of any of the fingers 266 in responseto depression ofa digit key 24, as previously described. thus will movethese parts 2'H--213 to their broken line positions-of Fig. 3, whichresults in rearward movement of the link 265 by the pin 215 to itsposition of Fig. 3, which isthe same actuation ofthis link 2635 as thateifected in. response toforward movement of the I cancelling; crank 11This "is: truewbecause such forward movement oi cancelling crank 1|results in swinging of the lever I56 from its position of Fig. 1 to thatof Fig 3, whereby its tooth 26i cooperating with the notch 262 will movethe pawl 263 and the link 265 rearwardly. During the final increment ofsuch movement of the link 265- in response to forward swinging of thecancelling crank it, the upper arm 261 of the pawl 263 will strike thestud 269 to impart counter-clockwise movement to the pawl relative tothe link 265 to disengage the notch 262 from the tooth 261. These partsare shown in Fig. 3 in the positions assumed just prior to suchdisengagement, and complete forward swinging of the cancelling crank i 1will impart additional counter-clockwise movement to the lever l53 fromitsposition of Fig. 3. Consequently, even though the cancelling crank 14be held inits forward actuated position, tie link 265 and connectedparts will be returned from their rearmost-positions of Fig. 3 bythespring 2 2 to their normal positions of l, with the top edge of themain armor the pawl 263 underlying the tooth 26!. As differentiatingfrom such actuation of the link 265 in response to manual operation ofthe cancelling crank 11, this link 265 and its connected parts will notbe returned to their normal positions. of Fig. 1 by the spring 2H.following-their actuation in response to depression of a digit key 24until the latter leased.

Such rearward movement of the link 265, in response either to actuationof a digit key 24 or the cancelling crank 11, will release the latchpawl or holding detent 222 from the teeth 232 of the ratchet slide bar226 in response to the resulting movement of the bell crank lever 2!!)from its position of Fig. l to that shown in Fig. 3. Since the pawl 255normally is held out of engagement with the teeth 251 of slide bar226because spring 252 :maintains this pawl and the hell-crank lever 25lin its position of Fig. 1, such release otthe holding pawl 222 fromthe'teeth 232 results in forward slidingof the ratchet bar 226 onthestuds 226 under the influence of spring 25 which urges the lower end ofthe lever 246 forwardly, until the forward end of the-ratchet slide bar226 strikes stop pin 225. These several parts thus assume their positionof Fig. Bupon actuation of a-machine control key,andthe forwardmovementof the ratchet slide bar 226-per mits closing of the switch,comprising contact members 2362 nd. 235, to energize the motor M. Itwill be readily understood, of course, that the holding pawl 222.willwbe returned to engaging relationship with the rearinost of theteeth 232 immediately thereaften'either as the "cancelling crank 1tpasses approximately the middle of its forward swinging movement, orupon manual release of the digit key 24, the depression of whichinstituted disengagement of the pawl 2 22.

As previously explained, all of the several parts of the instant timeswitch mechanism normally are disposed in their positions of: Fig. 1. Inresponse to @the' above described energization of the motor :44; thelarge gear 261 is rotated-in a clockwise direction fromthis normalposition. The. first cam rol1er'259 of the leading uppermost pair ofrollers 259'; 26!] illustrated in this figure thereupon moves the lug258 forwardly to swing the bellcrank lever 25iclockwiseabout theshaft2'45-and against the actionsof'spring 232 to a positiorrto the left ofthat shown. in Fig. 4. This:forward movement of 'thelower end'fof thelever 25f carries-thestud'shaft "-254 forwardly and permits the spring256 to lift the nose of pawl 255 into engagement with the lower edge ofratchet slide bar 226. Continued rotation of gear 26! carries theleading cam roller 259 beyond the lug 258 and moves the second camroller 26!: of this pair to its position of Fig. 4. Immediately upondisengagement of the first cam roller 259 from the lug 258, the spring252 functions to return the bell crank lever 25! in a counter-clockwisedirection about the shaft 245 to its position of Fig. 4, wherein thenose of pawl 255 engages the rearmost tooth 25'! of ratchet slide bar226. The second cam roller 260 is provided to assist the spring 252 andpositively insure complete return movement of this lever 25! to itsposition of Fig. 1. During such final increment of return movement ofthe lever 25L thus positively eil'ected by cam action of roller 265against the upper cam edge of lug 258 from the position illustrated inFig. 4, pawl 255 is moved rearwardly to slide the ratchet bar 225rearwardly the distance of one tooth 251, whereupon continued movementof these parts results in disengagement of the pawl 255 from rack bar225 by virtue of engagement of its tail piece. against rod 253. In themeantime, the holding pawl 222 has been moved out of engagement with therearmost or first tooth 232 and into engagement with the second suchtooth to maintain the slide bar 225 in such intermediate position (asshown in Fig. 4)

As illustrated herein, three such latch teeth 232 and two actuatingteeth 25'] are provided on the slide bar 22%. Consequently, repetitionof such incremental movement rearwardly of the bar 226 eiiected by thesecond pair of cam rollers 2-59, 260 as they in turn actively engage camlug 258 in the continued rotation of gear 26!, will move rack bar 226from its position of Fig. t back to its normal position of Fig. 1.During the last portion of such incremental rearward movement of theslide bar 226, the insulated roll 233 will move switch member 234rearwardly out of contact with switch member 235 to break the circuitand cause de-energization of motor 44. The overrunning of the motor andmembers driven thereby after such de-energization, due to the momentumof the parts, will insure return of the several members to theirposition of Fig. 1. It will be readily understood that the particulargear ratio herein illustrated as obtaining between pinion 265 and gear26!, and the specific number of latching and actuating teeth 232 and 251shown, may be varied to obtain any desired predetermined time intervalbetween closing of the motor switch in response to manual operation of amachine control member and automatic reopening of such switch. In otherwords, depending upon the particular construction, normal mode ofoperation and operating cycle time of the specific machine in which theinstant invention is to be incorporated, the person employing thisinvention may so design the several parts, as hereinbefore described, asto obtain the most satisfactory predetermined delayed shut-oil of themotor. The specific embodiment of the invention herein illustrated anddescribed greatly facilitates its incorporation in the type ofcalculating machine disclosed in the referenced prior patents, since itmakes use of the mechanism old therein and is particularly adapted forsuch incorporation by virtue of the assembly of the major portion of thenovel mechanism in the sub frame 22?, 228. It will be understood,however, that it is not intended to limit the scope of this invention tothe specific embodiment herein disclosed, nor to its use only with thattype of machine illustrated in such patents.

It is thought that the invention and its attendant advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made in the form, construction .and arrangementof the parts without departing from the spirit and scope of theinvention or sacrificing all of its material advantages, the formhereinbefore described and illustrated in the drawings being merely apreferred embodiment.

I claim:

1. In a time switch for a motor operated machine having a plurality ofmanually operable members for selectively controlling machine operationand a motor controlling switch normally maintained open by aswitch-opening member, spring means for retracting said switch-openingmember from normal position, a latch pawl normally engaging saidswitch-opening member to prevent retraction thereof by said springmeans, a link pivotally connected to said pawl and spring-urged tonormally maintain the pawl in latching engagement with saidswitch-opening member, and connections actuated by said manuallyoperable members to move said link in response to actuation of one ofsaid manually operable members to disengage said pawl from saidswitch-opening member and automatically releasable from said link toefiect ire-engagement of said pawl with said switch-opening member,whereby each successive operation of any one of said manually operablemembers will disengage said pawl from said switch-opening member.

2. A time switch according to claim 1, wherein said connections includea toothed lever rockable by a said manually operable member, a bellcrank lever pivotally mounted on said link and having a first armspring-urged into engagement with said toothed lever and a second armupstanding from said link, and a stationary stop against which saidsecond arm is moved to disengage said first arm from said toothed leverat the end of the latching pawl disengaging movement imparted thereby tosaid link to enable immediate return of said link to normal position.

3. In a time switch for a motor operated machine having a plurality ofmanually operable members for selectively controlling operation and amotor controlling switch normally maintained open by a switch-openingmember, spring means for retracting said switch-opening member fromnormal position, a latch pawl normally engaging said switch-openingmember to prevent retraction thereof by said spring means, a linkpivotally connected to said pawl and springurged to normally maintainthe same in latching engagement with said switch-opening memher, a rockshaft having a plurality of upstanding fingers operatively associatedrespectively with said manually operable members, and connectionsinterposed between said rock shaft and said link for actuating thelatter to disengage said pawl from said switch-closing member uponactuation of any one of said manually operable members.

4. In a time switch mechanism for a motor operated machine having amotor controlling switch normally maintained open by a slide mechanismmanually releasable to effect closing of the switch, means forcyclically advancing said slide mechanism in step-by step movements tore-open said motor controlling switch, comprising a gear train driven bythe machine motor and including a driven gear, a lever, an advancingpawl pivotally mounted on said lever and springurged toward engagement"with said slide mechanism,xstationary stop means, spring means formoving said lever. to'impart advancing movement to .said pawl andvsubsequently to move said pawl into engagement with said stop means toefiect disengagement thereof from said slide mechanism, andcooperatingcam means carried by said driven gear and said lever' forimparting retractive movement to said lever to tension said springmeans.

5. Time switch mechanism according to claim 4, wherein said cam meansincludes a member carriediby said driven gear operable after tensioningand release of said spring means to positively insure complete pawladvancing movement ofsaid lever.

6. Time switch mechanism for motor operated calculating machineswhich'have an electric circuit through the motor,-a switchior'controlling said-circuit, and a plurality ofcontrol membersselectively operable manually to control'operation of themachineycomprisinga ratchet member normallyengaging said'switch tomaintain the same in open position, 'means constraining saidratchetmember for-movement out of engagement with said switch, detentmeans normallyengaging said'ratchetmember to prevent movement thereof bysaid constraining means, link mechanism operable in response to manualactuation of a said'contrormember to-disengage said detent' meansfromsaid'ratchet member to enable. closing of said switch by saidconstraining means, spring means operable to return said link mechanismfollowingsuch' actuation of said control..member to re-engage-saiddetent means with said ratchet member, a ratchet member driving pawl, asecond spring means normally maintaining saidpawl out of engagement-withsaid-ratchet member, and means cyclically operable bysaid motor tosnccessively' tension said second spring 'means and release the same toactuate; said driving pawl to move said ratchet member toward switchopening position against the action of" said constraining means.

'7. Time switchmechanismaccording to: claim 6, wherein said cyclicallyoperable means comprises a cam member operable after tension and releaseof said second spring means to'pos'itively effect" complete actuation ofsaid driving pawl.

Refercnccs Cited in. the file Of this Patent

